The proposed research is based on the hypothesis that hemoglobin encapsulated in an appropriate artificial membrane would function like normal intraerythrocyte hemoglobin. Encapsulation would keep the hemoglobin in circulation longer and maintain its concentration and environment at appropriate levels for adequate oxygen release. Cross-linked hemoglobin should be an ideal membrane because it can be metabolised. Previous investigators have shown that hemoglobin can be cross-linked to form an insoluble polymer, but no one has reported the use of such a polymer to form an artificial red-cell membrane. Our preliminary studies demonstrated that this can be accomplished with liquid membrane technology. Artificial red-cell membranes composed of cross-linked hemoglobin can be made to resist hemolysis so that they can be dried and rehydrated. Since lyophilized hemoglobin is viable when reconstituted, these artificial red cells should have adequate shelf life for use as emergency blood supplies. This technique should allow more efficient use of hemoglobin from donor blood. In addition, we plan to develop a synthetic plasma basal on a perfusion medium we have developed.